Need schooling
The V8-6-4 was introduced in 1981, and was killed in 1981. I knew that was a flop because a family friend bought one and that thing had more miles on the hook than it did under its own power.
The guy was flush with cash so he went and bought another car and scrapped that one. Since one of his businesses was a wrecking yard with a crusher he shot it full of holes, drained the oil and water out of it and sat in it with his foot on the throttle until it shat itself.
Then it was crushed. Too bad video cameras weren’t around back then. That would have been entertaining to watch.
The Cadillac EFI came out in late 1974 for the 1975 model year. It was dropped sometime in the late 70’s. They said it was over cost but I suspect it was just because it was pretty much finicky garbage and GM got tired of dealing with it.